• LHCb CPV charm

A new method to measure time integrated CP asymmetry of D0 singly Cabibbo-suppressed decays to the CP-even final states K+K− and π+π− is developed. The method is applied to decays produced in pp collision and collected by the LHCb experiment between 2016 and 2018 at the center-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 5.7 fb-1. The strong-interaction decay D∗+ → D0π+ is used to infer the flavour of the D0 meson at production. The measured asymmetries are expressed as the difference between the raw asymmetries of the decays of interest and the raw asymmetry of the D0→Ks0π+π− calibration channel. The final results are:
Δ ACP(K+K−) = ACP(K+K−)−ACP(Ks0π+π−)=0.194±0.049%
Δ ACP(π+π−) = ACP(π+π−)−ACP(Ks0π+π−)=0.402±0.057%
where the uncertainties are statistical and the central values are blinded. The final uncertainty improves the world average statistical uncertainty, currently dominated by LHCb, by a factor of about 2.5.